<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>行高</title>
        <style>
           div{
            border:1px solid #000;
            height:60px;
           }
           #two{
            line-height: 60px;
           }
           #three{
            line-height:30px;
           }
        </style>
    </head>
    <body>
        <div>没有进行任何设置</div>
        <div id="two">设置了文本行高<br>第二行</div>
        <br><br><br><br>
        <div id="three">文本行高不一样<br>第二行</div>
    </body>
</html>